The proposed research program is concerned with the implementation of a new clinical method of measuring the quality of medical care that counts cases of unnecessary disease and disability and unnecessary untimely deaths. First, conditions are listed in which the occurrence of a single case of disease or disability or a single untimely death would justify asking "Why did it happen?" Second, conditions are selected in which critical increases in rates of disease, disability, or untimely death can serve as indexes of the quality of care. These negative indexes that cover the entire spectrum of medical care are similar in principle to those of maternal and infant mortality. The study of their usefulness in solving health care problems is underway in order to learn how to determine the level of health in general and special populations, and the effects of economic, political, and other environmental factors upon it, in order to aid in the evolution of a national system of medical care and the development of a national health program. Research will be directed towards applying these outcome measurements to answer questions immediately relevant to improving the quality and efficiency of medical care in this country and througout the world.